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    <meta charset="UTF-8">
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    <title>Document</title>

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<body>
    <script>
        let a=5, b=3;
        console.log(a+b);
        console.log(a-b);
        console.log(a/b);
        console.log(a*b);
        console.log(a%b);
        //简写
        console.log(a+=5);
       console.log("________________________");
        let n1=1;
        let n2=2;
        let n3=n1+ ++n2; //++n2,先加再于前面的运算
        alert(n3);
       console.log(n3);
       

    </script>
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